SIRT3 sulfhydrylation by hydrogen sulphide: A novel approach to prevent ferroptosis and atrial fibrosis

Background

Hydrogen sulfide (H₂S) has been shown to counteract ferroptosis and atrial fibrosis, yet the underlying mechanisms remain incompletely understood. This study aims to investigate how H₂S regulates ferroptosis to alleviate atrial fibrosis.

Methods

In vivo and in vitro models of atrial fibrosis were established using Angiotensin II (Ang-II) to modulate the expression of SIRT3, β-catenin, and ferroptosis markers. Western blotting was employed to analyze changes in proteins related to ferroptosis and fibrosis. Histological evaluations, including Hematoxylin and Eosin (HE), and Masson's staining were performed to assess atrial fibrosis. Cardiac ultrasound was used to assess left atrial function in vivo. In vitro, reactive oxygen species (ROS) levels and iron staining were used to monitor ferroptosis and oxidative stress.

Results

In atrial tissue from patients with AF, significant increases in ferroptosis markers and atrial fibrosis were observed. In both animal and cell models of atrial fibrosis, reduced sulfhydrylated SIRT3 and elevated β-catenin expression were associated with increased ferroptosis and fibrosis markers. Treatment with NaHS, a donor of H₂S, reversed these changes, reducing both ferroptosis and fibrosis. Importantly, inhibition of sulfhydrylated SIRT3 further upregulated β-catenin, exacerbating ferroptosis and fibrosis. However, blocking β-catenin effectively alleviated Ang–II–induced ferroptosis and fibrosis in the atrial fibrosis model.

Conclusion

H₂S alleviates atrial fibrosis and inhibits ferroptosis by upregulating SIRT3 sulfhydrylation and antagonizing the Wnt/β-catenin signaling pathway. These findings suggest that targeting the H₂S-SIRT3-β-catenin signaling axis may offer a promising therapeutic strategy for atrial fibrosis and associated arrhythmias.